Caterpillar feeder for strands



May 3, 1960 H. o. LUTCKE CATERPILLAR FEEDER FOR sTRANDs Filed June lO, 1957 ooooooooooooooo United States Patent CATERPILLAR FEEDER FOR STRANDS Helmut Otto Liitcke, Dusseldorf-Ratingen, Germany, as-

smior, by mesne assignments, to Beteiligungsund Patentverwaltungsgesellschaft mit beschrankter Haftung, Essen, Germany Application June 10, 1957, Serial No. 664,766

Claims priority, application Germany June 13, 1956 3 Claims. (Cl. 203-227) The present invention relates to caterpillar feeding mechanisms for cables, ropes and strands as they are used to pull such cables, ropes or strands through cable strandng or insulating machines. Wherever in this specifcation and claims the broad term strand is used, it is to be understood to include any longitudinally extending elements of indefinite length, such as cables, ropes, wires, relatively slender strips, ribbons, or tubes, made of any material.

fw Caterpillars heretofore known generally grip the cable by means of two chains linedwith profiled rubber treads, said chains being mechanically, hydraulically, or pneumatically pressed on the cable by means of a bar. In spite of the provision of such proled rubber treads, the cables are sometimes unduly compressed under the action of pressure from opposite sides, so that the shape of the cable is distorted and/ or its insulation is damaged.

ln order to obviate this drawback, or to at least considerably lessen it, caterpillar pulling mechanisms with more than two tracks have been recently used. As a result of this, the unit surface pressure is reduced and, at the same total pressure and with the same tension, the caterpillar mechanism can be designed shorter. Since the profiles of the treads engage the cable around a smaller circumferential surface than in two-track caterpillar mechanisms, the cable will not be readily damaged.

It is an object of the present invention to provide in a caterpillar pulling mechanism having three tracks displaced 120 with respect to one another one unobstructed side for the unhindered insertion or threading of the cable and to operatively connect these three tracks to a common drive shaft disposed at one side with regard to the caterpillar mechanism.

In order to feed pre-shaped sector cores or conductors and at strands, the device for applying pressure to the tracks is suitably designed in such a way, that the latter become adapted to the shape of these cores, conductors or strands. This is accomplished, according to another object of the invention, by providing a pressure bladder to engage the heads of a larger number of plunger-s arranged one behind the other, the ends of said plungers being equipped with shoes serving to guide the tracks. The bladder is provided in a displaceable, preferably rockably suspended beam or bar. By varying the air pressure in this bladder, the pressure applied by the tracks may be adjusted as desired. In place of compressed air, liquid under pressure may be applied to the bladder. The three pressure bladders are suitably connected to a common pressure-equalizing device. In order to obtain an uninterrupted guide way for the tracks, the ends of the guide shoes interengage one another, i.e. they are hingedly connected to each other, forming links from plunger to plunger.

Still further objects and the entire scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilledV in the art from this detailed description.

In the drawings,

'Figure 1 illustrates schematically a side view of a caterpillar mechanism feeding a cable or the like through a cable insulating machine;

Figure 2 is a side view, partially in section, of a caterpillar mechanism for pre-shaped sector conductors or cores;

Figure 3 is a cross section through the caterpillar mechanism along the line II-II of Figure 2; and

Figure 4 is a schematic showing of the drive means for the tracks.

Referring now in more detail to the drawings, in'Figure 1, A is the winding up cable drum, B is a plasticv extrusion machine, C is a cooling trough, D is a caterpillar pulling or feeding mechanism and E is a winding reel. A cable, conductor or strand Si), fed from the cable drum A, is to be provided with insulation in the extrusion machine B and cooled in the trough C, whereby the pulling lforce exerted by the caterpillar mechanism D will not damage the insulation just formed. During the pulling of pre-shaped sector conductors, i.e., conductors which have already obtained a shape other than circular corresponding to their position in the sector cable, care has to be taken that these conductors are not distorted when passing through the pulling mechanism D.

The caterpillar mechanism, as shown in Figures 2 and 3, is provided with three endless chains 1, 2, 3, which are displaced towards each other. These chains are equipped with rubber treads 4, 5, 6, respectively, and are passed over sprocket wheels of which the sprocket wheels 7, 8, 9 are the drive wheels (see Figure 4). The associated second sprocket Wheels of each sprocket wheel pair (10 in Figure 2) is hingedly mounted on an elbow lever 11, so that the chain can be stretched or tensioned. The tension is obtained from a spring 12, the force of which is adjustable by means of a threaded bolt 13. The drive sprocket wheels 7, 8, 9 are driven by a drive shaft 14, disposed at one side of the caterpillar mechanism, via bevel gears 60 to 67 and intermediate shafts 15, 68, 69 and 70, in such a way, that all of these sprocket wheels, 7, S and 9 operate at the same circumferential velocity and in the same direction. The drive shaft 14 is connected to the driving gears of the cable insulating machine by means of a velocity-regulating arrangement. 'I'he pulling speed of the tracks can be read on a tachometer 16 coupled with the sprocket wheel shaft 15.

The caterpillar mechanism has three beams, 17, 13, 19 which are hingedly or rockably mounted ou lever pairs 20/21, 22/23, and 24/25, respectively. Figure 2 shows the beam 17 hanging on a pair of levers 20 and 21. The three lever pairs are connected to one another in such a manner that their rocking movements take always simultaneously and uniformly, so that all of the beams are moved towards the center of the caterpillar mechanism or are retracted from the same in unison. This is obtained, as shown in the embodiment of Figures 2 and 3, by means of a threaded shaft 27 manually rotatable with the aid of a handwheel 26 and by means of a sprocket 28 mounted on this shaft 27, said sprocket 28 being connected to a sprocket 30 via a chain 29. The sprocket 30 is mounted on a threaded shaft 31. The threaded shafts 27 and 31 transmit the rotating movements imparted to them via arms 32, 33, 34 and pins 35, 36, 37 to the lever pairs 20/21, 22/23, 24/25 mounted on these pins which are journalled in stationary bearings ndicated at 35', 36', and 37', respectively. Thus,

the beams 17, 18, 19 can be radially adjusted in a simple l manner to readily comply with any particular operatingr condition. The beams or frames 17, 18, 19 are provided with rails upon which the chains of the tracks slide, in order to feed smoothcables. Sensitive cables or sector-shaped conductors, particularlyVthose which are Y plungers 38, 39, 40, distributed over the length ofV these beams, these plungers being radially displaceable with respect to the cable and extend with their heads in chambers 41, 42, 43, formed in the beams 38, 39, 40, respectively. The ends of these plungers 3 8, 39, 40 protruding from the beams are equipped with guide shoes 44,. 45, 46, respectively, for the tracks. Bladders 47, 48, 49 are inserted in the chambers 41, 42, 43, respectively, said bladders being connectedv to a compressor 53` for air or liquid. If pressure is applied to these bladders, the plungers 3S, 39, 40 move towards the center of the caterpillar mechanism, whereby the guide shoes 44, 45 and 46 are pressed onrthe tracks. These guide shoes are hingedly mounted on the plungers and engage one another at their ends, i.e., they llexibly interconnect adiacent plungers. The pressure force of the tracks act.- ing on the cable can be controlled in a simple manner by varying the pressure in theV bladders.

I claim:

1. A caterpillar feeding mechanism for strands,` comprising three endless caterpillar tracksV displaced"120 In accordance K,

with respect to one another and adapted and arranged to circumferentially grip and feed said strands inserted between said tracks, a common drive shaft for said caterpillar tracks at one side of said mechanism, means to operatively connect said drive shaft to said caterpillar tracks, three frames, each of said frames supporting one of said caterpillar tracks, adjustable means to Vdisplace said frames in radial direction with respect to said strands, a. pressure chamber in each of said frames,v apressure medium withinY said chambers, a plurality of plungers displaceabl'y mounted in said frames and extending with one of their ends to said chambers to be acted upon by said pressure medium, and guide shoes hingedlyv mounted on the other ends of said plungersfto slidingly engage and guide said tracks opposite the strand-engaging sides thereof. Y Y

2. A caterpillar feeding mechanism according to claim l, wherein the ends of adjacent guide shoes on each of said plungers are interengaging one another. v

3. A caterpillar feeding mechanism according to claim 2, wherein said ends of said guide shoes are hingedl-y connected to one another to form an articulated uninterrupted guide way for said track riding theron.

Y References Cited in the tile of this patent `UNTED STATES PATENTS 

